Alignment in ShapenetCore v2

Question

For the v1 release of Shapenetcore, the README states:

"NOTE: The OBJ files have been pre-aligned so that the up direction is the +Y axis, and the front is the +X axis. In addition each model is normalized to fit within a unit cube centered at the origin. The X-Y plane is the bilateral symmetry plane for most categories."

I just wanted to check to make sure this is true for the v2 release as well, and also if there's anything in the README for v1 that does not also apply to v2. Thanks!

Answer 1

For ShapeNetCore v2, the front is the -Z axis with +Y still being the up axis (the Z-Y plane is the bilateral symmetry plane for most categories).  The models are exported to OBJ using a different pipeline that attempts to fix 1) reflection issues in ShapeNetCore v1 (you will see this in car models) 2) texture/material issues.  Note that some models are not present in ShapeNetCore v2 (we are working on an updated version that will include all models).